Question : work with a file name that changes based on that days date

I need help with visual basic code for the following:

The file name is in this format:  rmr121709.lmc

I need to select the file in a directory that matches that days date, then rename the file to oldfile.txt, run a script on the file then rename the file back to rmr & todays date & .lmc.

Answer : work with a file name that changes based on that days date

Dim fileName As String = "rmr" & DateTime.Today.ToString("MMddyy") & ".lmc"
File.Delete("oldfile.txt")
File.Move(fileName, "oldfile.txt")

' ... run script here

File.Move("oldfile.txt", fileName)